Scientists from Hong Kong, together with colleagues from mainland China, presented the first of their kind MicroLED displays with LEDs in the deep ultraviolet range. This is a solution for the production of semiconductors by lithographic method without the use of masks. If the development is implemented in chip production, it will lead to lower prices for lithography equipment with traditional light sources such as mercury lamps, and even make them unnecessary.
Image source: Hong Kong University of Science and Technology
Work on the topic was published in the journal Nature back in October of this year. It was later awarded the title of one of the ten breakthrough technologies developed in China in 2024. It must be admitted that the transition to maskless production using LED MicroLED displays will significantly simplify production lines and their maintenance, as well as reduce the cost of maintaining infrastructure – water, electricity, ventilation, etc.
LED emitters ranging in size from 3 to 100 microns were manufactured (grown) on wafers using an alloy of aluminum and gallium nitride (AlGaN). The wavelength of the LEDs is 270 nm, but this value can be varied, achieving the highest efficiency in a fairly wide range of UV frequencies (210–400 nm). The experimental display for projection without masks reached a resolution of 2540 dpi. Researchers plan to increase the resolution to 8K and higher. The radiation flux density was 396 W/cm². The flow was stable and adjustable, promising defect-free production over long periods of use.
Image source: Nature 2024
«Compared to other presented designs, our innovation features smaller device size, lower drive voltage, higher external quantum efficiency, higher optical power density, larger matrix size, and higher display resolution. These key improvements in [UV MicroLED] performance make this study the best in the world in all respects,” conclude the researchers from the Hong Kong University of Science and Technology, who led the work.